KR20010086111A - Chroman derivatives - Google Patents

Abstract

The present invention relates to chroman derivatives of the general formula

Formula I

Where

R ¹ is acyl, —CO—R ⁵ or an amino protecting group having 1 to 6 carbon atoms;

R ² is H or alkyl of 1 to 6 carbon atoms;

R ³ and R ⁴ are each independently of each other H, alkyl having 1 to 6 carbon atoms, CN, Hal or COOR ² ;

R ⁵ is unsubstituted or phenyl mono- or di-substituted with alkyl of 1 to 6 carbon atoms, OR ₂ or Hal;

X is (H, H) or O;

Hal is F, Cl, Br or I.

The derivatives and salts thereof can be used as intermediate products in the synthesis of medicaments.

Description

Chromman derivatives {CHROMAN DERIVATIVES}

The present invention relates to chroman derivatives.

The present invention relates to a chroman derivative of formula (I) and salts thereof:

Where

R ¹ is acyl, —CO—R ⁵ or an amino protecting group having 1 to 6 carbon atoms;

R ² is H or alkyl of 1 to 6 carbon atoms;

R ³ and R ⁴ are each independently of each other H, alkyl having 1 to 6 carbon atoms, CN, Hal or COOR ² ;

R ⁵ is unsubstituted or phenyl mono- or di-substituted with alkyl of 1 to 6 carbon atoms, OR ₂ or Hal;

X is (H, H) or O;

Hal is F, Cl, Br or I.

The invention also relates to optically active forms, racemates, enantiomers, hydrates and solvates such as alcoholates of the compounds.

Similar compounds are disclosed in EP 0 707 007.

The present invention has been completed, in particular, on the object of developing novel compounds which can be used as intermediates in the synthesis of medicaments.

It has been found that compounds of formula (I) and salts thereof are important intermediates in the preparation of medicaments, in particular medicaments acting on the central nervous system.

The present invention relates to Chromman derivatives of formula (I) and salts thereof.

Unless otherwise indicated throughout this application, the radicals R ¹ , R ² , R ³ , R ⁴ , R ⁵ and X have the meanings indicated in Formula I and Formula II described below.

In formula (I) and formula (II) described below, alkyl has 1 to 6, preferably 1, 2, 3 or 4 carbon atoms. Alkyl is preferably methyl or ethyl, also propyl, isopropyl, in addition to butyl, isobutyl, secondary-butyl or tert-butyl. Acyl has 1 to 6, preferably 1, 2, 3 or 4 carbon atoms. Acyl is especially acetyl, propionyl or butyryl. R ² is preferably H, in addition to methyl, ethyl or propyl. R ³ and R ⁴ are each preferably H. R ⁵ is preferably, for example, phenyl, o-, m- or p-tolyl, o-, m- or p-hydroxyphenyl, o-, m- or p-methoxyphenyl, or o-, m- or p-fluorophenyl. The R ¹ radical is an acyl, —CO—R ⁵ or else an amino protecting group known per se, with acetyl being particularly preferred.

The term "amino protecting group" is generally known and is suitable for protecting (blocking) the amino group from chemical reactions and relates to a group that can be easily removed after the desired chemical reaction has taken place at another position in the molecule. have. Typical groups of this type are especially unsubstituted acyl, aryl, alkoxymethyl or aralkyl groups. Since the amino protecting groups are removed after the desired reaction (or series of reactions) have occurred, their nature and size are not so important, but groups having 1 to 20 carbon atoms, especially 1 to 8 carbon atoms, are preferred. The term "acyl group" is to be interpreted in its broadest sense in the methods and compounds of the present invention. The term includes acyl groups derived from aliphatic, araliphatic, aromatic or heterocyclic carboxylic acids or sulfonic acids, and also especially alkoxycarbonyl, aryloxycarbonyl and especially alkoxycarbonyl groups. Examples of acyl groups of this type include alkanoyls such as acetyl, propionyl, butyryl; Aralkanoyl, for example phenylacetyl; Aroyl such as benzoyl or toluyl; Aryloxyalkanoyl, for example phenoxyacetyl; Alkoxycarbonyls such as methoxycarbonyl, ethoxycarbonyl, 2,2,2-trichloroethoxycarbonyl, BOC (tert-butoxycarbonyl), 2-iodoethoxycarbonyl; Aralkyloxycarbonyls such as CBZ (carbenzoxycarbonyl, also referred to as “Z”), 4-methoxybenzyloxycarbonyl, FMOC (9-fluorenylmethoxycarbonyl); Or arylsulfonyl such as Mtr (4-methoxy-2,3,6-trimethylphenylsulfonyl). Preferred as amino protecting groups are BOC and Mtr, in addition CBZ or FMOC.

Compounds of formula (I) may have one or more chiral centers and therefore exist in various stereoisomeric forms. Formula I includes all of these forms.

The present invention is also characterized in that the compounds of formula (II) are hydrogenated with the aid of an enantiomer-multimerization catalyst, according to claim 1 of the Relates to a manufacturing method:

Where

R ¹ , R ² , R ³ and R ⁴ are each as defined in claim 1;

X is O.

The present invention is also characterized in that X in formula I according to claim 1 is characterized in that the compound of formula II is hydrogenated with the aid of an enantiomer-multimerization catalyst and then reduced in a conventional manner. H, H) Chromane derivatives and also methods for preparing the salts thereof:

Formula II

Where

R ¹ , R ² , R ³ and R ⁴ are each as defined in claim 1;

X is O.

In particular, enantiomer-multimerized (2-acetylaminomethyl) chroman-4- by hydrogenation of (2-acetylaminomethyl) chromen-4-one with various enantiomerically pure rhodium-diphosphane complexes It has been found that hot can be obtained.

The present invention also relates to a process for the preparation of a chroman derivative of formula (I), characterized by the use of transition metal complexes as enantiomer-multimerization catalysts.

Especially preferably, the catalyst is a transition metal complex comprising a metal selected from the group consisting of rhodium, iridium, ruthenium and palladium.

The invention also relates to a process for the preparation of a chroman derivative of formula (I), characterized in that the transition metal complex in which the transition metal is complexed with a chiral diphosphane ligand is used as a catalyst.

Examples include the following ligands:

(S) -Et Dufos ((S) -EtDuphos):

BINAP:

(S, S) -Chiraphos:

(S, S) -DIOP:

(S, S) -Skephos (BDPP):

(S, S) -BPPM:

(R, R) -Norphos:

(S, R) -BPPFOH:

(S, R) -PFctBu:

Depending on whether the (R) or (S) enantiomer of the ligand is selected in the catalyst, it is determined whether the (R) enantiomer of the product is obtained in excess or the (S) enantiomer is obtained in excess.

Precursors used for chiral ligands are, for example, Rh (COD) ₂ OTf (rhodium-cyclooctadiene triflate), [Rh (COD) Cl] ₂ , Rh (COD) ₂ BF ₄ , [Ir (COD) Cl] ₂ , Ir (COD) ₂ BF ₄ or [Ru (COD) Cl ₂ ] _x .

Compounds of formula (I) and also starting materials for the preparation thereof are methods known per se, for example under the reaction conditions known per se or appropriate for the reaction, for example, unless otherwise indicated. Prepared by methods described in Houben-Weyl, Methoden der organischen Chemie (Methods of Organic Chemistry), Georg-Thieme-Verlag, Stuttgart). It is also possible to use various variations of the methods known per se, although not mentioned in more detail herein.

If desired, starting materials may also be formed in situ so that they can be further reacted immediately to provide a compound of formula I without being isolated from the reaction mixture.

Some of the compounds of formula II are known. Unknown compounds can be readily prepared by methods similar to the known compounds. Compounds in which X is O in formula (II) are converted according to the invention to compounds of formula (I) in which X is O using hydrogen gas in the presence of an enantiomer-multimerization catalyst in an inert solvent such as methanol or ethanol.

In addition, examples of suitable inert solvents include hydrocarbons such as hexane, petroleum ether, benzene, toluene or xylene; Chlorinated hydrocarbons such as trichloroethylene, 1,2-dichloroethane, carbon tetrachloride, chloroform or dichloromethane; Alcohols such as isopropanol, n-propanol, n-butanol or tert-butanol; Ethers such as diethyl ether, diisopropyl ether, tetrahydrofuran (THF) or dioxane; Glycol ethers such as ethylene glycol monomethyl or monoethyl ether (methyl glycol or ethyl glycol), ethylene glycol dimethyl ether (diglyme); Ketones such as acetone or butanone; Amides such as acetamide, dimethylacetamide or dimethylformamide (DMF); Nitriles such as acetonitrile; Sulfoxides such as dimethyl sulfoxide (DMSO); Carbon disulfide; Nitro compounds such as nitromethane or nitrobenzene; Esters, for example ethyl acetate, and optionally also mixtures of said solvents or mixtures of these with water.

The reaction time of the enantioselective hydrogenation reaction is from minutes to 14 days, depending on the conditions used, and the reaction temperature is from 0 ° C to 150 ° C, generally from 20 ° C to 130 ° C. Typically, the ratio of catalyst / substrate is from 1: 2000 to 1:50, particularly preferably from 1: 1000 to 1: 100. The reaction time is then 3 to 20 hours, for example. The hydrogenation reaction is carried out under hydrogen of 1 to 200 bar, preferably 3 to 100 bar.

Compounds of formula (I) wherein X is O, as described above, are compounds of formula (I) wherein X is O using hydrogen gas in the presence of an enantiomer-multimerization catalyst in an inert solvent such as methanol or ethanol After hydrogenation with, the 4-oxo group in formula (I) is converted to a methylene group according to known conditions, thereby converting to a compound in which X in formula (I) is (H, H). The reduction reaction is preferably carried out using hydrogen gas under a transition metal catalyst (eg by hydrogenation on Raney nickel or Pd-carbon in an inert solvent such as methanol or ethanol).

Compounds in which R ³ and R ⁴ in formula I are each COO-alkyl, for example R ^{3 in} formula I using NaOH or KOH, water-THF or water-dioxane in water at temperatures between 0 ° C. and 100 ° C. And R ⁴ are each converted to a compound that is COOH.

R ¹ radicals in the compounds of the formula (I) can be removed not only with strong acids, for convenience TFA (trifluoroacetic acid) or perchloric acid, depending on the protecting group used, but also with other inorganic strong acids (eg Hydrochloric acid or sulfuric acid), strong organic carboxylic acids (eg trichloroacetic acid) or sulfonic acids (eg benzenesulfonic acid or p-toluenesulfonic acid). Additional inert solvents may be used but are not necessary. Suitable inert solvents are preferably organic solvents such as carboxylic acids (eg acetic acid), ethers (eg tetrahydrofuran or dioxane), amides (eg dimethylformamide), halogenated hydrocarbons ( Dichloromethane), in addition to alcohols (eg methanol, ethanol or isopropanol) and also water. Also mixtures of the above solvents may be used. TFA is preferably used in excess without adding additional solvent, and perchloric acid is used in the form of a mixture of acetic acid and 70% perchloric acid in a ratio of 9: 1. The reaction temperature is from about 0 ° C to about 50 ° C for convenience, and the reaction is preferably carried out at 15 ° C to 30 ° C.

The BOC group is preferably removed at 15 ° C. to 30 ° C. using TFA in dichloromethane or using about 3 to 5 N hydrochloric acid in dioxane. Acetyl groups are removed according to conventional methods (methods described in P. J. Kocienski, Protecting Groups, Georg Thieme Verlag, Stuttgart, 1994).

Protecting groups (e.g., CBZ or benzyl) that can be hydrocracked can be removed, for example, by treatment with hydrogen in the presence of a catalyst (e.g. a noble metal catalyst such as palladium on a support such as carbon for convenience) Can be. Suitable solvents in this case are solvents as described above, in particular for example alcohols (eg methanol or ethanol) or amides (eg DMF). As a rule, hydrocracking is carried out at a temperature of about 0 ° C. to 100 ° C. and a pressure of about 1 to 200 bar, preferably at a temperature of 20 ° C. to 30 ° C. and a pressure of 1 to 10 bar.

Bases of formula (I) can be converted to the corresponding acid addition salts using an acid, for example by reacting the same amount of base with the acid in an inert solvent such as ethanol and then evaporating. Acids suitable for this reaction are in particular acids which provide physiologically acceptable salts. Thus, inorganic acids such as sulfuric acid, nitric acid, hydrohalic acid (eg hydrochloric acid or hydrobromic acid), phosphoric acid (eg orthophosphoric acid) or sulfamic acid can be used, in addition to organic acids, in particular aliphatic, cycloaliphatic, Araliphatic, aromatic or heterocyclic monobasic or polybasic carboxylic acids, sulfonic acids or sulfuric acid, for example formic acid, acetic acid, propionic acid, pivalic acid, diethylacetic acid, malonic acid, succinic acid, pimelic acid, fumaric acid, maleic acid, lactic acid, Tartaric acid, malic acid, citric acid, gluconic acid, ascorbic acid, nicotinic acid, isnicotinic acid, methanesulfonic acid, ethanesulfonic acid, ethanedisulfonic acid, 2-hydroxyethanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid, naphthalenyl sulfonic acid Phonic acid, naphthalenesulfonic acid and lauryl sulfate can also be used. Salts with physiologically acceptable acids, such as picrates, can be used to isolate and / or purify the compound of formula (I).

On the other hand, the compounds of formula (I) are converted to the corresponding metal salts, in particular alkali metal or alkaline earth metal salts, or corresponding ammonium salts with bases (eg sodium hydroxide, potassium hydroxide, sodium carbonate or potassium carbonate) Can be.

The invention also relates to the use of the compounds of formula (I) for use as intermediates in the synthesis of medicaments. Suitable medicaments are described, for example, in EP 0 707 007.

Thus, the present invention in particular

(a) hydrogenating a compound of formula II wherein X is O with the aid of an enantiomer-multimerization catalyst;

(b) obtained by crystallizing enantiomerically pure (R) compounds of formula (I) in which X is O from (R) compounds of formula (I) and (S) compounds of formula (I) step;

(c) reducing in a conventional manner the enantiomerically pure (R) compound, wherein X in formula (I) obtained is O;

(d) removing the R ¹ radical from the (R) compound in which X in formula (I) obtained is (H, H); And

(e) The obtained (R)-(chroman-2-ylmethyl) amine is converted into its acid addition salt and the salt is reacted in a known manner to give (R) -2- [5- (4-fluoro Obtaining only phenyl) -3-pyridylmethylaminomethyl] chrom, optionally converting it to an acid addition salt thereof, wherein the (R) enantiomer is also added after step (c) or step (d) (R) -2- [5- (4-fluorophenyl) -3-pyridylmethylaminomethyl], characterized in that it can be recovered by crystallization from an enantiomer-multimerization (R, S) mixture. The use of a compound of formula (I) according to claim 1 in the following claims for use in synthesizing chromman and salts thereof:

Formula I

Formula II

In the above formulas,

R ¹ is as defined in claim 1;

R ² , R ³ and R ⁴ are each H;

X is as defined above.

The invention further relates to the use of a compound of formula (I) for use as an intermediate in the synthesis of medicaments that act on the central nervous system.

Throughout this application, all temperatures are expressed in degrees Celsius. In the following examples, "traditional workup" means adding water as needed, adjusting the mixture to a pH of 2 to 10 if necessary according to the composition of the final product, extracting with ethyl acetate or dichloromethane and then By a separation, removal, drying over sodium sulfate, evaporation, and purification of the residue by chromatography on silica gel and / or crystallization. R _t is the value obtained on silica gel.

Experimental data (preparation of the complex, hydrogenation, analysis method):

All reactions were performed under inert conditions (ie under anhydrous and anoxic reaction conditions).

1. Preparation of catalyst / substrate solution:

Example 1.1

11.2 mg of Rh (COD) ₂ OTf (rhodium-cyclooctadiene triflate) was dissolved in 5 ml of methanol and cooled to 0 ° C. Then a cooling solution of 1.1 equivalents of bisphosphane (eg, 12.6 mg of (R, R) -skephos) in 5 ml of methanol was added. After stirring for 10 minutes at room temperature, the complex solution was treated with a substrate solution consisting of 110 mg of (2-acetylaminomethyl) chromen-4-one in 10 ml of methanol.

Example 1.2

51.4 mg of [Rh (COD) Cl] ₂ is dissolved in 4 ml of a 5: 1 toluene / methanol solvent mixture and 5 ml of toluene, 1 ml of methanol and 1.1 equivalents of bisphosphane (eg 130.6 mg Treated with a solution consisting of (R) -BINAP). 1 ml of this catalyst complex solution was added to 510.8 mg of (2-acetylaminomethyl) chromen-4-one dissolved in 15 ml of toluene and 3 ml of methanol.

2. Enantiomer Selective Hydrogenation

The catalyst / substrate solution to be hydrogenated was charged to an autoclave backed by a protective gas. The atmosphere of protective gas was replaced by several times flushing with hydrogen (1-5 bar H ₂ atmosphere). A batch similar to that in Example 1.1 above was reacted under hydrogen pressure of 5 bar even at room temperature. Best results were obtained when a catalyst similar to that in Example 1.2 was used under hydrogen pressure of 80 bar at 50 ° C. In general, the hydrogenation reaction was terminated after 15 hours.

3. Sampling and Analysis Methods

Samples were taken in protective gas flowing back. The complex was separated by column chromatography on silica gel (eluent: ethyl acetate) before measuring enantiomeric excess. Enantiomeric excess of the hydrogenation product was determined on chiral HPLC:

Column: Daicel Chiralcel OJ (inner diameter × length / mm: 4.6 × 250)

Eluent: n-hexane: i-propanol = 9: 1

Flow rate: 0.8 ml / min (18 bar, 28 ° C.)

Detection: UV 250 nm

Retention time: R _t (R) = 27 minutes, R _t (S) = 29 minutes.

Concentration of the crude hydrogenation solution precipitated the product. An increase in enantiomeric excess was detected using fractional crystallization methods.

4. Further reduction

After confirming that the conversion reaction was terminated, the keto group was reduced using palladium-carbon as a one-pot process. The crude ketone solution obtained from the homogeneous hydrogenation reaction contains palladium-carbon with 10% by weight of moisture (for example Pd / C with 100 mg of moisture for 1 g of (2-acetylaminomethyl) chromen-4-one). And 1 ml of glacial acetic acid. The hydrogenation reaction was carried out for 14 hours at a hydrogen pressure of 7 bar and 50 ℃.

5. Post-Processing and Analysis Methods

Palladium-carbon was removed by filtration. Enantiomeric excess of the hydrogenation product was determined on chiral HPLC:

Column: Daicel Chiralcel OJ (internal diameter × length / mm: 4.6 × 250)

Eluent: n-hexane: i-propanol = 9: 1

Flow rate: 0.8 ml / min (18 bar, 28 ° C.)

Detection: UV 250nm

Retention time: R _t (R) = 25 minutes, R _t (S) = 27 minutes.

During the reduction to palladium-carbon, the enantiomeric excess did not change. Concentration of the crude hydrogenation solution precipitated the product. An increase in enantiomeric excess was detected using fractional crystallization methods.

In the table, Rh represents rhodium, Ir represents iridium, Et represents ethyl, MeOH represents methanol, iPrOH represents isopropanol, Tol represents toluene, and% ee represents enantiomeric excess (%). RT indicates room temperature.

Claims (11)

Chromane derivatives of formula (I) or salts thereof Formula I Where R ¹ is acyl, —CO—R ⁵ or an amino protecting group having 1 to 6 carbon atoms; R ² is H or alkyl of 1 to 6 carbon atoms; R ³ and R ⁴ are each independently of each other H, alkyl having 1 to 6 carbon atoms, CN, Hal or COOR ² ; R ⁵ is unsubstituted or phenyl mono- or di-substituted with alkyl of 1 to 6 carbon atoms, OR ₂ or Hal; X is (H, H) or O; Hal is F, Cl, Br or I. Enantiomers of the compound of formula I according to claim 1. The method of claim 1, (a) N- (4-oxochromen-2-ylmethyl) acetamide; (b) N- (chroman-2-ylmethyl) acetamide; (c) (S) -N- (4-oxochromen-2-ylmethyl) acetamide; (d) (R) -N- (4-oxochromen-2-ylmethyl) acetamide; (e) (S) -N- (chroman-2-ylmethyl) acetamide; Or (f) (R) -N- (chroman-2-ylmethyl) acetamide. A process for preparing a chroman derivative or a salt thereof, wherein X is O in formula I according to claim 1, characterized in that the compound of formula II is hydrogenated with the aid of an enantiomer-multimerization catalyst: Formula II Where R ¹ , R ² , R ³ and R ⁴ are each as defined in claim 1; X is O. Chromium derivatives according to claim 1 wherein X is (H, H), characterized in that the compound of formula II is hydrogenated with the aid of an enantiomer-multimerization catalyst and then reduced in a conventional manner. Method for preparing the salt thereof: Formula II Where R ¹ , R ² , R ³ and R ⁴ are each as defined in claim 1; X is O. The method according to claim 4 or 5, A process for preparing a chroman derivative of formula (I), characterized by the use of a transition metal complex as an enantiomer-multimerization catalyst. The method according to any one of claims 4 to 6, A process for preparing a chroman derivative of formula (I) characterized by using as a catalyst a transition metal complex comprising a metal selected from the group consisting of rhodium, iridium, ruthenium and palladium. The method according to any one of claims 4 to 7, A process for preparing a chroman derivative of formula (I), characterized in that the transition metal complex complexed with a chiral diphosphane ligand is used as a catalyst. Use of a compound of formula (I) according to claim 1 for use as an intermediate in the synthesis of a medicament. Use of a compound of formula (I) according to claim 1 for use as an intermediate in the synthesis of a medicament acting on the central nervous system. (a) hydrogenating a compound of formula II wherein X is O with the aid of an enantiomer-multimerization catalyst; (b) obtained by crystallizing enantiomerically pure (R) compounds of formula (I) in which X is O from (R) compounds of formula (I) and (S) compounds of formula (I) step; (c) reducing in a conventional manner the enantiomerically pure (R) compound, wherein X in formula (I) obtained is O; (d) removing the R ¹ radical from the (R) compound in which X in formula (I) obtained is (H, H); And (e) The obtained (R)-(chroman-2-ylmethyl) amine is converted into its acid addition salt and the salt is reacted in a known manner to give (R) -2- [5- (4-fluoro Obtaining only phenyl) -3-pyridylmethylaminomethyl] chrom and converting the acid addition salt thereof as necessary, wherein the (R) enantiomer is also added after step (c) or step (d) (R) -2- [5- (4-fluorophenyl) -3-pyridylmethylaminomethyl], characterized in that it can be recovered by crystallization from an enantiomer-multimerization (R, S) mixture. Use of a compound of formula (I) according to claim 1 for use in synthesizing Cromman and salts thereof Formula I Formula II In the above formulas, R ¹ is as defined in claim 1; R ² , R ³ and R ⁴ are each H; X is O or (H, H).